Voice over IP – Quality matters.

“Sorry…. you’re breaking up… Hello? could you repeat that please?”

What price Quality of speech? What is acceptable speech quality on a phone line to you? What influences your perception at any one given moment?

I often get asked : “why should I pay you for a VoIP service when I can use Skype?”. I thought I’d write a bit about my take on VoIP quality.

There’s VoIP and there’s VoIP. There’s good quality voice and there’s not so good quality voice.  When Storm kicked off our VoIP offering back in February 2004, our Sales team were often faced with some serious skepticism – especially from IT Managers who had “been there, done that, wanna see my scars?”, referring to some voice over IP solution they’d tried and failed. The guys who often took the plunge in 2004 were the FD’s – keen to cut costs.  It did help that our solution was capex free for the customer and ROI did not need to feature.

Our customers being businesses, many of whom depend on their voice comms to keep the daily bread coming in – we’ve a fair portion of the BPO market here – will not tolerate bad quality voice. But the problem is this : quality is in the ear of the hearer. How often do I witness people battling to get a good signal on a GSM phone, accepting “poorer than PSTN” quality, calling back once or twice during a call and seldom thinking of logging a fault. I do it myself. But let my desk phone be faint, or noisy, or break-up, and my blood pressure starts to rise! Unconscious perceived value in the mobility of the GSM handset and acceptance of a norm that has arisen.

In a bandwidth-lean environment like South Africa, where uncontended last mile IP connectivity for an internet services provider is still prohibitively expensive (in November 2006), we have had to resort to an actively managed IP network. MPLS based virtual private networks with QoS, the order of the day. Quality VoIP, but at a price.

So it was with interest that I read two articles, reporting research into recent trends in the quality of VoIP over the open internet. Both coming to different conclusions.

One, referenced on the Gartner blog, quoting a recent VoIP study conducted by Brix Networks indicating that VoIP (not over a managed IP network) quality is erratic. The study asserts that quality has gone down over the past couple of years, but Gartner’s reading of the data leads them to think otherwise. They point out that a cut of the most recent data shows that VoIP quality is improving – but then it’s still 5% down on Feb ’05. Brix have a cute little app you can run on your desktop that measures and plots MOS scores to various difference global destinations – I ran it for a day or two until Google Desktop (which is it requires) irritated me enough to get rid of it. Some of the screenshots I’ve pasted into a Word doc if you’re interested - check under "Recent Presentations".

The 2^nd, a study by Minacom, seems to indicate that “VoIP phone service worldwide "now sounds better and connects faster than the standard public-switched phone network (PSTN)."” Better than the PSTN?!? They go on to point out that Brix’s tests were based on PC-to-PC type of VoIP, rather than VoIP such as we at Storm deploy, where we manage the IP network from the Gateway attached to a PBX to the last point before it is converted into a TDM signal again (if at all).

Better than the PSTN though? That brings me to an interactive white paper I love to quote (it’s a bit like a party trick for geeks! ;). The guys at Global IP Sound (who developed the iLBC codec used by Skype) put it together. I love it. VoIP has the potential to deliver broadcast quality audio on a voice call if all the elements (including bandwidth) are in place. PSTN cannot and will never. In the interests of squeezing every last drop of bandwidth out of the “pipes” we use, we purposefully degrade the quality of a VoIP call to the point where it is efficient, yet only just acceptable. That’s the line we have to walk, until the price of decent quality bandwidth falls..

That’s me.

Btw. If anyone can point me to the results of some guys who have been doing regular pings around the world for the last decade or so and publish the results, please drop me a line.

Comments

[DaveG]

Hi Riaan,

Great to hear that. Your comment is a little light on detail w.r.t. what exactly you have found! ;)

Care to give us a bit more on how it all works?

Dave

[Riaan Welman]

For 2 years I was looking for a VoIP solution to offer my clients. Found it!! Our VoIP is good, incomming and outgoing calls to all networks at excellent savings.